Evaluation Of Left Atrial Structure And Function In PAF Patients After CPVI By 2D-STI And RT-3D Techniques

Background:Recent years,circumferential pulmonary vein isolation has achieved certain curative effect in the treatment of atrial fibrillation,but it has a certain recurrence rate.More and more people begin to pay attention to the changes and recurrence of left atrial function after operation.Studies have shown that left atrial function can predict the recurrence of atrial fibrillation.Some studies have evaluated circumferential pulmonary vein isolation in patients with atrial fibrillation by two-dimensional echocardiography,spectral Dopp The changes of left atrial structure and function before and after CPVI and the prediction of atrial fibrillation recurrence proved that ultrasound parameters had high value in evaluating left atrial function and atrial fibrillation recurrence after CPVI,but there were somevlimitations.Two-dimensional echocardiography was influenced by left atrial geometry in evaluating left atrial function,and spectral Doppler was affected by measurement angle in evaluating left atrial function.The degree,the pressure gradient between left atrium and lef:t ventricle,and the pre-and post-load state of the heart can not accurately evaluate the left atrium function.Recently,new techniques such as real-time three-dimensional ultrasound imaging(RT-3D)and two-dimensional speckle tracking imaging(2D-STI)can accurately assess the structure and function of left atrium,suggesting that these two new techniques can more accurately assess the changes of left atrial function after operation and predict the recurrence of atrial fibrillation.Objective:This study was designed to evaluate the left atrial changes of structure and function in different cardiac cycles before and after Circumferential Pulmonary Vein Isolation(CPVI)in patients with paroxysmal atrial fibrillation(PAF)by combining two new techniques,echocardiography RT-3 D and 2D-STI,with conventional transthoracic echocardiography.Assessing the risk of recurrence of AF patients after CPVI,providing an objective basis for the development of follow-up treatment and assessment of prognosis,at the same time,which plays an important role in improving the quality of life of patients.Methods1.Study group:42 patients with PAF who underwent CPVI in our hospital from October 2017 to December 2018 were selected for data collection.All 42 patients underwent CPVI successfully,8 of whom were lost during follow-up,and finally collected completely data of 34 patients.Control group:32 physical examination subjects were selected as the control group.2.All patients underwent echocardiographic examinations including conventional transthoracic echocardiography,pulsed Doppler flow spectrum,tissue Doppler myocardial imaging(TDI),two-dimensional speckle tracking imaging(STI)and RT-3D one day before RFC A,three days and three months after operation.LAD,LAUDD and LALRD,LVEDD and LVESD were measured routinely,and LVEF was calculated.E peak and A peak of mitral diastolic velocity were measured at early and late stages,and E/A ratio was calculated.Weaving speed E’and late diastolic tissue velocity a’,and the E/e’ ratio were obtained.Four cardiac cycle images with clear cross-sectional images of apical four-chamber heart,two-chamber heart and three-chamber heart were taken and analyzed offline.3.Offline analysis with STI technology:The peak strain(Ss,Se,Sa)and strain rate(SRs,SRe,SRa)of the anterior,inferior,posterior,lateral and septal segments of the left atrium at systolic,early and late diastolic stages of the left ventricle were measured,and the mean peak strain rate(mSRs,mSe,mSa)and the mean peak strain rate(mSRs,mSRe,mSa)of the walls were measured.The left atrial stiffness LAST(Left atrial stiffness)can be calculated according to the value of mSs and E/e’ratio.Meanwhile,the electromechanical conduction time(EMT)of each segment of the left atrium was measured on the strain curve of the left atrium,the time from the starting point of P wave to the peak strain of the left atrium in late diastole on the synchronous electrocardiogram,and the mean electromechanical conduction time(mEMT)of the left atrium were calculated.4.Left atrial minimum volume(LAVmin),left atrial maximun volume(LAVmix),left atrial pre-systolic volume(LAVp)were obtained by RT-3D technology.Left atrial ejection fraction(LAEF)and active left atrial ejection fraction(LAVp)could be calculated according to the volume obtained.Left atrial Active ejection fraction(LAAEF),passive ejection fraction(LAPEF),cardiac dilatation index,and Pipeline Function Index.Results1.Comparison of basic data between PAF group and control group:There was no significant difference in age and HR between the two groups by two independent samples.There was no statistieally significant difference in gender,age,heart rate and underlying disease after 2 tests.(P>0.05).2.Comparison of conventional ultrasound parameters:After two independent sanplest test,the left atrial diameter(LAAPD,LAUDD,LALRD)in the PAF group was higher than that in the control group,and the difference was statistically significant.The E peak and E/A were significantly increased.(P<0.05),A peak decreased significantly(P<0.05);e,,af decreased compared with the control group(P<0.05).LAVmax in the PAF group was significantly higher than that in the control group(P<0.01)5 LAVmin was increased(P<0.05),LAEF,left atrial duct function index,and left atrial dilatation index were all decreased,all of which were statistically significant(P<0.05).3.Comparison of preoperative strain rate parameters between PAF group and control group:The strain parameters of PAF group and control group before CPVI were tested by two independent samplest test.The results showed that the strain of left atrium wall of PAF group was lower than that of the control group.Among them,interval wall Se,Sa,side wall Ss,Sa,front wall Ss,Sa,Ss and Se of the lower wall;Ss and Se of the back wall are significantly reduced(P<0.01),and lower wall Sa(P<0.05).Comparison of mEMT results:Compared with preoperative,the left atrial mEMT increased in the CPVI group 3 days after operation(P<0.05),and the left atrial mEMT were 3 months after surgery.Days decreased(P<0.05).4.Comparison of preoperative strain rate parameters between PAF group and control group:Compared with the control group before CPVI,the strain rate and overall strain rate of the systolic side wall,inferior wall and posterior wall of the PAF group were lower than those of the control group(P<0.05).);early diastolic wall,anterior wall,posterior wall strain rate and total strain rate decreased;late diastolic lateral wall,anterior wall,posterior wall strain rate and total strain rate decreased(P<0.05).5.Comparison of strain rate before operation,3 days and 3 months after operation in the postoperative sinus rhythm group:The systolic,early diastolic,and late diastolic strain rates of the sinus rhythm were lower than those before surgery(P<0.01).The strain rate in March was higher than that before and 3 days after surgery(P<0.01).6.Atrial fibrillation rhythm group before surgery,3 days and 3 months after surgery should be compared with the rate of surgery:postoperative atrial fibrillation recurrence preoperative,postoperative 3 days and 3 months,postoperative 3 months interval SRe Side wall SRs,SRa,lower wall SRe,posterior wall SRe,SRa,GLSRa were significantly higher than those at 3 days postoperatively(P<0.01),and significantly decreased compared with preoperative(P<0.05).The left atrial function was further reduced in patients with unsuccessful conversion.7.Comparison of strain rate parameters of left atrium wall between sinus rhythm group and atrial fibrillation recurrence group in 3 months after operation:Three months after operation,the sinus rhythm group and the atrial fibrillation rhythm group showed two independent samplest-test results:SRs,SRe,SRa of the atrial fibrillation group interval,side wall,anterior wall,inferior wall and posterior wall at 3 months postoperatively.,and GLSRa decreased significantly(p<0.01),mEMT,GLSRs decreased(p<0.05),the difference was statistically significant GLSRe was also reduced,but the difference was not statistically signifieant.8.Comparison of left atrial structure and RT-3DE functional paraneters before and after operation in patients with postoperative sinus rhythm:There was no significant difference in LAUDD,LALRD,LAEF,LAAEF,and left atrial dilatation index between the three days after operation(P>0.05).LAUDD and LALRD were compared with preoperative and postoperative 3 days and 3 months.The inner diameter was significantly reduced(p<0.01),and the LAEF,LAAEF,and left atrial dilatation index were signifieantly higher than those before and 3 days after surgery(p<0.01).This result suggested that the left atrial pump function recovered after 3 months.9.Comparison of left atrial structure and RT－3DE function parameters before and after operation in atrial fibrillation rhythm groupAfter operation,the LALRD of the atrial fibrillation rhythm group decreased after 3 months,compared with 3 days after surgery,and the LAEF and LAAEF decreased compared with the preoperative and postoperative 3 days.The left atrial assist pump fimction is further reduced.10.Comparison of left atrial structure and RT-3DE functional parameters between sinus rhythm group and atrial fibrillation recurrence group in 3 months after operation Compared with the sinus rhythm group,the LAAPD,LAUDD,LALRX),LAV min,LAVmax,and LAVP increased,LAAEF,PFI,and CDI decreased,and the above indicators could predict the recurrence of atrial fibrillation in advance.Conclusions1.The echocardiographic 2D-STI and RT-3D techniques can be used to quantitatively analyze the changes of left atrial structure and function in PAP patients before and after RFCA.They can also be used to evaluate the effect of radiofrequency ablation and predict the recurrence of atrial fibrillation in advance.2.Circumferential pulmonary vein isolation can reverse the left atrial remodeling in patients with atrial fibrillation,reverse the electrical remodeling,and improve the left atrial structure and function in patients with atrial fibrillation.3.Circumferential pulmonary vein isolation can lead to a temporary reduction of left atrial function,increased stiffness and prolonged mechanical conduction time,while in the left atrium 3 months after operation,stiffness and mechanical conduction time are reduced,and the improvement of PAF function is significant.